BACKGROUND:These big black balls are thrown down by Bowser and King Bob-Omb to crush anyone who dares to challenge them! These iron spheres bounce down the path, in hopes of killing unsuspecting hikers. They also appear in a large metal cage where Goombas and windup springboards lurk.

EVOLUTION:They first appeared in Super Mario World where they were dark-grey coloured.
When Iron Balls returned in Super Mario 64 they were a darker black.